A better way to get an object without throwing an exception

# This will return None if not found, as opposed to raising an exception
classroom = Classroom.objects.filter(pk=pk).first()

But what we want to do

from django.shortcuts import get_object_or_404

# This will return a HTTP 404 response if the objects does not exist
classroom = get_object_or_404(Classroom, pk=pk)

The right way to try catch

try:
    classroom = Classroom.objects.get(pk=pk)
except Classroom.DoesNotExist:
    classroom = None
questions = Question.objects.filter(classroom=classroom).order_by('-created')